5.3 Setting B
NOTE
Setting B is sometimes needed when the following parts are
replaced:
The OPC belt, charge corona wires, charge/grid power pack, or flash power supply unit
CAUTION
1. Usually, you do not have to do setting B even after replacing the above items. The
flash, grid, and bias output levels are automatically adjusted by the process control.
However, if the flash, grid, or bias shift step are significantly changed since the parts
replacement, you cannot know how many steps have been shifted up or down at the
next check of the data. Therefore, perform setting B only when the shift steps are
significantly changed after replacing the above items.
2. Before setting B, clean the charge corona unit and light path (the mirrors, lens,
reflectors, and exposure glass).
3. Install all exterior covers when doing setting B. External light may affect the OPC
potential.
4. Do not continue free run (more than 100 copies) from the [4-01] screen. Toner
density in the cleaning unit will be reduced and the cleaning carrier’s power to attract
toner will lower. This may cause toner scattering from the cleaning unit. This problem
occurs also when:
1) Making more than 100 free run copies from the [4-01] or [4-02] screen.
2) Turning on the main motor for more than 5 minutes using the I/O test mode in the
service tools.
3) Making more than 100 white copies.
If dirty copy images appear due to toner scattering from the cleaning unit, try to do
the cleaning carrier forming.
5. After setting A, setting B does not have to be done.
6. When the OPC belt is replaced, V SG might lock. So, access service tool [4-02] and
make a free run to check V SG operation. If it is locked, perform setting C (release the
VSG lock).
The flash, grid, and bias output levels are changed by the VL, VD, and VR compensations (the
process control) when OPC belt fatigue, or change of the operating environment (temperature and
humidity) occurs, or the light path (the mirrors, lens, etc.) or charge corona unit becomes dirty. After
cleaning the charge corona unit and light path, if any shift steps (compensated values) remain, they
represent the level of the wear of the OPC belt, charge corona wires, xenon lamp, etc.
Checking the shift steps in the [4-01] screen is useful to know the level of wear of such parts and to
find out machine condition. However, when the parts described above are replaced, the output level
for the flash, grid, or bias might change. When the process control compensates the output levels
automatically, the shift steps are shifted up or down. The purpose of setting B is to reset the shift
steps to 0 and to enable the check of the shift steps in the [4-01] screen.
For example, consider the grid output when the OPC belt is replaced. After the OPC belt is
replaced, process control changes the grid output to obtain the target VD value as the OPC
potential for the black pattern. As a result, the grid output is normally reduced. As the grid shift step
increases negatively, performing settting B reduces the grid setting step and reset the grid shift step
to 0. You can know how many steps have been shifted up or down at the next check of the data
after replacing the OPC belt.
Setting B 1 July 1994
5-8
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